This invention relates generally to chain tensioning apparatus, and specifically to such apparatus suitable for use with the chain drive system of a hay baler.
Modern balers are rather complex pieces of machinery which translate rotary input power into numerous other timed rotary and reciprocal movements. In many baler designs, particularly the class of baler described herein, it has been found most advantageous and efficient to transfer timed rotary to rotary power through a chain and sprocket arrangement.
In most applications there are very few problems encountered with chain drive systems; however, the power stroke of a baler plunger subjects the drive to cyclic forces which tend to cause the chain to flex and thereby skip teeth on one or more of the sprockets. Also, it is not altogether uncommon for the flywheel shear bolt to fail and cause the chain drive to temporarily, though violently, reverse its direction and cause slack in the normally taut portion of the chain. For whatever reason such may occur, any change in the relationship between a timing chain and its supporting sprockets can be very inconvenient and potentially damaging to the equipment.
Prior art devices for maintaining tension on baler chain drives have proved unsatisfactory in many instances because of the cyclic loading characteristics described. Unless the varying forces can be absorbed, with the simultaneous maintenance of tension, the chain will either skip or damage the rigidly held tensioning device. The instant invention is directed to a device which overcomes the inadequacies of the prior art and effectively improves the overall operational characteristics of a baler.